Class 10 Science Chapter 14 Source of Energy

Class 10 Science Chapter 14 Source of Energy The answer to each chapter is provided in the list so that you can easily browse throughout different chapters NCERT Class 10 Science Chapter 14 Source of Energy and select need one.

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Class 10 Science Chapter 14 Source of Energy

Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 10 Science Chapter 14 Source of Energy Solutions for All Subjects, You can practice these here…

Source of Energy

Chapter – 14



Page -243 

Q.1. What is a good source of energy?

Ans :- A good source of energy would be one 

( i ) Which would do a large amount of work per unit volume or mass.

( ii ) Be easily accessible. 

( iii ) Be easy to store and transport and 

( iv ) Perhaps most importantly, be economical. 

Q.2. What is a good fuel? 

Ans :- A good fuel :- 

( i ) It should be easily available.

( ii ) Its calorific value should be large.

( iii ) It should burn easily.

( iv ) It should produce no smoke and should not leave any residence. 

( v ) Its combustion rate should be steady and controllable. 

( vi ) It should burn at controllable rate. 

Q.3. If you could use any source of energy for cooking your food, which one would you use and why? 

Ans :- We would prefer to use L.P.G. or Gobar gas. Because these gases have high calorific value, not produce pollution, easily available and is economical. 

Page – 248 

Q.1. What are disadvantages of fossil fuels? 

Ans :- Disadvantages of fossil fuels are :- 

( i ) The end product is carbon dioxide which causes green house effect. 

( ii ) When petrol is burnt, harmful substances like unburnt hydrocarbons, carbon monoxide, oxides of nitrogen sulphur are processed. These cause acid rain and thus soil and water pollution give innumerable problem to health. 

Q.2. Why are we looking at alternative sources of energy? 

Ans :- We are looking for a alternative sources of energy because conventional sources of energy 

( i ) Like coal and petroleum are not going to last long. 

( ii ) Are mostly non-renewable sources of energy 

( iii ) Cause pollution. They are costly. 

Q.3. How has the traditional use of wind and water energy been modified for our convenience? 

Ans :- The energy of the wind can be usefully employed by working of wind-mills. Wind mill helps us to produce electricity. Energy of the wind can be used to do mechanical work i.e. to lift water from the well and run a grain grinding machine.

To use water energy for producing electricity, a large number of high rise dams are constructed on the suitable river spots to obstruct the flow of water and collect water in large reservoirs. The kinetic energy of the following water is converted in to potential energy. Then the water form the high level in the dam is carried through pipes to the turbine at the bottom of the dam. Thus the potential energy of falling water is converted into electrical energy. 

Page – 253 

Q.1. What kind of mirror-concave, convex or plane mirror would be best suited for use in a solar cooker? Why? 

Ans :- A plane mirror is used because it reflects all the light falling on it to the desired place. 

Q.2. What are the limitations of the energy that can be obtained from the oceans? 

Ans :- Due to alteration of the moon, there are high and low tides in the sea. Tidal energy is harnessed by constructing a dam across a narrow opening to the sea. A turbine fixed at the opening of the dam converts tidal energy to electricity. The limitation to such dams is due to scarcity of locations where such dams can be constructed. 

Ocean thermal energy of the sea or ocean is also used to produce electricity but these plants operate if the temperature difference between water at the surface and water at the depth up to 2 km is 20°C or more. 

Q.3. What is geothermal energy? 

Ans :- Energy derived from hot spots beneath the earth is called geothermal energy. 

Q.4. What are the advantages of nuclear energy? 

Ans :- Nuclear energy is preferred to fossil energy, hydro energy, thermal energy etc for the following reasons.

( i ) A smaller space is required to get nuclear energy as compared to space required to harness hydro energy, thermal energy etc. 

( ii ) It produces much more energy than other conventional sources.

( iii ) It causes lesser pollution then fossil energy. 

Page – 253 

Q.1. Can any source of energy be pollution free? Why or why not? 

Ans :- No source of energy can be pollution free because even if it is clean, its assembly could have caused environmental damage. 

Q.2. Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not? 

Ans :- Hydrogen is cleaner fuel than CNG because hydrogen when burnt in presence of oxygen produces harmless water vapour. But when C.N.G. burnt produces carbon dioxide. 

Page – 254 

Q.1. Name two energy sources that you would consider to be renewable. Give reasons for your choices.

Ans :- ( i ) Energy derived from biomass is a renewable source of energy because waste products are continuously produced. 

( ii ) The energy derived from flowing water, wind, sun and ocean are renewable sources because these sources can be harmless into energy so long as the present solar system exists. 

Q.2. Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choice. 

Ans :- Coal and petroleum are two exhaustible sources of energy. They are present in limited quantity in nature and can be exhausted by human activities. 


Q.1. A solar water heater can not be used to get hot water 

( a ) A sunny day. 

( b ) A cloudy day.

( c ) A hot day.

( d ) A windy day.

Ans :- ( b ) A cloudy day. 

Q.2. In Which of the following is not an example of a biomass energy source? 

( a ) Wood.

( b ) Gobar-gas.

( c ) Nuclear energy.

( d ) Coal.

Ans :- ( c ) Nuclear energy.

Q.3. Most of the sources of energy we use represent stored solar energy. Which of the following is not ultimately derived from the Sun’s energy? 

( a ) Geothermal energy.

( b ) Wind energy.

( c ) Nuclear energy.

( d ) Biomass.

Ans :- ( c ) Nuclear energy.

Q.4. Compare and contrast fossil fuels and the Sun as direct sources of energy. 

Ans :- Similarity :- 

( i ) Both are natural sources of energy.

( ii ) Both are widely used sources of energy.

Contrast :- 

( i ) Fossil fuels are non-renewable. But the energy of Sun in renewable. 

( ii ) Fossil fuels causes lot of air pollution. But the energy of Sun pollution free. 

Q.5. Compare and contrast bio-bass and hydro electricity as sources of energy. 

Ans :- Similarity :- ( i ) Both are renewable sources of energy. 

( ii ) Working cost of both sources is very low. 

Contrast :- 

( i ) Large area of land get submerged under water in hydroelectric.

( ii ) Plant where as a very small area is used for biomass plants. 

Q.6. What ar the limitations of extracting energy from 

( a ) The wind? 

( b ) Waves? 

( c ) Tides? 

Ans :- ( a ) Limitations of wind energy :-

( i ) Need a large open space to couple a number of wind mills. 

( ii ) It is not available everywhere and at all the times. 

( iii ) Wind velocity must be sufficient. 

( b ) Limitations of extracting energy from waves :-

( i ) Wave energy is viable proposition only when and where the waves are very strong. This has constraints of time and location. 

( c ) Limitation of tidal energy :- 

( i ) Its cost is huge and is not possible to build such dams everywhere. 

( ii ) Huge amount of silt gets deposited on basins in the dams. 

Q.7. On what basis would you classify energy sources as :- 

( a ) Renewable and non-renewable? 

( b ) Exhaustible and inexhaustible? 

Ans :- ( a ) The energy sources that can be regenerated are called renewable sources of energy. 

Non-renewable sources are produced over millions of years under special conditions. Once consumed are not replaceable for a very long time. Fossil fuels like coal. Petroleum and natural gas are non-renewable sources. 

( b ) Exhaustible sources are non-renewable sources and inexhaustible sources are renewable sources. 

Q.8. What are the qualities of an ideal sources of energy? 

Ans :- Am ideal source of energy :- 

( i ) Which would do a large amount of work per unit volume or mass.

( ii ) Be easily accessible.

( iii ) Be easy to store and transport and 

( iv ) Perhaps most importantly be economical. 

Q.9. What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?

Ans :- Advantages :- ( i ) It does not produce any pollution.

( ii ) It provides cost free. 

Disadvantages :- ( i ) The efficiency of a solar cooker is very low. 

( ii ) It cannot be used for frying purpose. Solar cookers cannot be used at places where there is insufficient amount of sun shine. 

Q.10. What are the environmental consequences of the increasing demand for energy? What steps suggest to reduce energy consumption? 

Ans :- The demand of energy is increasing day by day. Exploiting any would no. source of energy may disturb the environment in one way or other. For example getting energy from fossil fuel may cause lot of pollution in air. 

Steps for reducing energy consumption :- 

( i ) Ease and cost of extracting energy from the source.

( ii ) The efficiency of the available technology. 

( iii ) Environmental impact of using that source.

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